Euphorbia, OIL OF, or OIL OF CAPER SPURGE, an extremely acrid fixed oil, obtained by expression, or by the aid of alcohol or ether, from the seeds of the Caper Spurge (Euphorbia lathyris), a plant common in many parts of Europe, and naturalised in some places in Britain (see SPURGE). Oil of euphorbia has much resemblance to croton-oil in its properties, although less powerful, and is sometimes used as a substitute for it, in doses of from three to ten drops. It is good for use only when recently extracted.